长沙一次暴雪天气过程的多普勒雷达回波特征  

Doppler Radar Echo Characteristics of a Snowstorm in Changsha

作　　者：胡媚 尹亮彬 唐明晖 Hu Mei;Yin Liangbin;Tang Minghui(Hunan Meteorological Bureau,Changsha 410118,China;Hunan Key Laboratory of Meteorological Disaster Preventing and Reducing,Changsha 410118,China;Hengyang Meteorological Service,Hengyang 421001,China)

机构地区：[1]湖南省气象台,湖南长沙410118 [2]气象防灾减灾湖南省重点实验室,湖南长沙410118 [3]衡阳市气象局,湖南衡阳421001

出　　处：《气象与减灾研究》2022年第1期22-30,共9页Meteorology and Disaster Reduction Research

基　　金：湖南省气象局短平快课题(编号:XQKJ22B004)。

摘　　要：针对2021年12月25—26日湖南长沙暴雪天气过程,以长沙多普勒天气雷达资料为主,分析此次过程回波强度、径向速度、雷达风廓线等的变化。结果表明:1)本次暴雪过程受冷空气、短波槽过境、700 hPa急流的共同影响;深厚的湿层、大气整层低于0℃、中层强的西南暖湿气流在强冷垫上爬升导致长沙出现暴雪。2)长沙暴雪时段,持续不断有25—30 dBz反射率因子生成,同时,垂直液态水含量和回波顶高偏低。3)降雪时段,径向速度表现出风场辐合、急流核增强、零速度线成直线等特征;预示着动力条件增强,为降雪的维持和增强提供了临近预报信息。4)垂直风廓线产品上,3.4—4.9 km高度风场由西北风为主转为偏西风再转为西南风,表征短波槽过境,动力条件有所增强;随着西南风强度和厚度的持续增加,降雪强度增强;后期风场再次转为西北风为主,对应的降雪逐渐减弱。Based on the Changsha station Doppler radar data, the variation of the echo intensity, radial velocity, radar wind profile of the blizzard process in Changsha, Hunan province from December 25 to 26, 2021 was analyzed. The results showed that: 1) This process was influenced by the combination of cold air, short-wave trough transit and 700 hPa jet stream. The deep wet layer, the whole layer temperature less than 0 ℃ and strong southwest warm and humid airflow in the middle layer climbing on the strong cold cushion leaded to the snowstorm in Changsha. 2) During the snowstorm, the vertical liquid water content(VIL) and the top height of the echo(TOP) were low. 3) During the snowfall period, the Doppler radial velocity diagram showed the features of wind field convergence, jet stream nucleus enhancement, and zero velocity line in a straight line. The wind field convergence and jet stream nucleus enhancement indicated the enhancement of dynamic conditions, which provided the proximity forecast information for the maintenance and enhancement of snowfall. 4) The vertical wind profile(VWP) analysis showed that the wind field at the height of 3.4-4.9 km changed from northwesterly wind to westerly wind and then to southwesterly, indicating the transit of a short-wave trough with enhanced dynamic conditions. As the intensity and thickness of the southwest wind continued to increase, the snowfall enhanced in the meantime. Later the wind field turned to northwest, corresponding to weakening of snowfall gradually. These above features provided useful information for the snowstorm nowcast forecast and warning.

关 键 词：暴雪 径向速度 雷达回波 垂直风廓线 

分 类 号：P415.2[天文地球—大气科学及气象学]